Type Point
  As Single x,y
End Type

Function inpolygon(p1() As Point,p2 As Point) As Integer
  #Macro isleft2(L,p)
    -Sgn(  (L(1).x-L(2).x)*(p.y-L(2).y) - (p.x-L(2).x)*(L(1).y-L(2).y))
  #EndMacro
  Dim As Integer index,nextindex
  Dim k As Integer=UBound(p1)+1
  Dim send (1 To 2) As Point
  Dim wn As Integer=0
  For n As Integer=1 To UBound(p1)
    index=n Mod k:nextindex=(n+1) Mod k
    If nextindex=0 Then nextindex=1
    send(1).x=p1(index).x:send(2).x=p1(nextindex).x
    send(1).y=p1(index).y:send(2).y=p1(nextindex).y
    If p1(index).y<=p2.y Then
      If p1(nextindex).y>p2.y Then
        If isleft2(send,p2)>=0 Then '=
          wn=wn+1
        End If
      End If
    Else
      If p1(nextindex).y<=p2.y Then
        If isleft2(send,p2)<=0 Then'=
          wn=wn-1
        End If
      End If
    End If
  Next n
  Return wn
End Function


Dim As Point square(1 To 4)  ={(0,0),(10,0),(10,10),(0,10)}

Dim As Point hole(1 To 4)    ={(2.5,2.5),(7.5,2.5),(7.5,7.5),(2.5,7.5)}

Dim As Point strange(1 To 8) ={(0,0),(2.5,2.5),(0,10),(2.5,7.5),_
                              (7.5,7.5),(10,10),(10,0),(2.5,2.5)}

Dim As Point exagon(1 To 6)  ={(3,0),(7,0),(10,5),(7,10),(3,10),(0,5)}

'printouts
For z As Integer=1 To 4
  Select Case z
    Case 1: Print "squared"
      Print "(5,5)  " ;Tab(12);
      If inpolygon(square(),Type<Point>(5,5)) Then Print "in" Else Print "out"
      Print "(5,8)  " ;Tab(12);
      If inpolygon(square(),Type<Point>(5,8)) Then Print "in" Else Print "out"
      Print "(-10,5)  " ;Tab(12);
      If inpolygon(square(),Type<Point>(-10,5)) Then Print "in" Else Print "out"
      Print "(0,5)  " ;Tab(12);
      If inpolygon(square(),Type<Point>(0,5)) Then Print "in" Else Print "out"
      Print "(10,5)  " ;Tab(12);
      If inpolygon(square(),Type<Point>(10,5)) Then Print "in" Else Print "out"
      Print "(8,5)  " ;Tab(12);
      If inpolygon(square(),Type<Point>(8,5)) Then Print "in" Else Print "out"
      Print "(10,10)  " ;Tab(12);
      If inpolygon(square(),Type<Point>(10,10)) Then Print "in" Else Print "out"
      Print
    Case 2:Print "squared hole"
      Print "(5,5)  " ;Tab(12);
      If Not inpolygon(hole(),Type<Point>(5,5)) And inpolygon(square(),Type<Point>(5,5)) Then Print "in" Else Print "out"
      Print "(5,8)  " ;Tab(12);
      If Not inpolygon(hole(),Type<Point>(5,8)) And inpolygon(square(),Type<Point>(5,8))Then Print "in" Else Print "out"
      Print "(-10,5)  " ;Tab(12);
      If Not inpolygon(hole(),Type<Point>(-10,5))And inpolygon(square(),Type<Point>(-10,5)) Then Print "in" Else Print "out"
      Print "(0,5)  " ;Tab(12);
      If Not inpolygon(hole(),Type<Point>(0,5))And inpolygon(square(),Type<Point>(0,5)) Then Print "in" Else Print "out"
      Print "(10,5)  " ;Tab(12);
      If Not inpolygon(hole(),Type<Point>(10,5))And inpolygon(square(),Type<Point>(10,5)) Then Print "in" Else Print "out"
      Print "(8,5)  " ;Tab(12);
      If Not inpolygon(hole(),Type<Point>(8,5))And inpolygon(square(),Type<Point>(8,5)) Then Print "in" Else Print "out"
      Print "(10,10)  " ;Tab(12);
      If Not inpolygon(hole(),Type<Point>(10,10))And inpolygon(square(),Type<Point>(10,10)) Then Print "in" Else Print "out"
      Print
    Case 3:Print "strange"
      Print "(5,5)  " ;Tab(12);
      If inpolygon(strange(),Type<Point>(5,5)) Then Print "in" Else Print "out"
      Print "(5,8)  " ;Tab(12);
      If inpolygon(strange(),Type<Point>(5,8)) Then Print "in" Else Print "out"
      Print "(-10,5)  " ;Tab(12);
      If inpolygon(strange(),Type<Point>(-10,5)) Then Print "in" Else Print "out"
      Print "(0,5)  " ;Tab(12);
      If inpolygon(strange(),Type<Point>(0,5)) Then Print "in" Else Print "out"
      Print "(10,5)  " ;Tab(12);
      If inpolygon(strange(),Type<Point>(10,5)) Then Print "in" Else Print "out"
      Print "(8,5)  " ;Tab(12);
      If inpolygon(strange(),Type<Point>(8,5)) Then Print "in" Else Print "out"
      Print "(10,10)  " ;Tab(12);
      If inpolygon(strange(),Type<Point>(10,10)) Then Print "in" Else Print "out"
      Print
    Case 4:Print "exagon"
      Print "(5,5)  " ;Tab(12);
      If inpolygon(exagon(),Type<Point>(5,5)) Then Print "in" Else Print "out"
      Print "(5,8)  " ;Tab(12);
      If inpolygon(exagon(),Type<Point>(5,8)) Then Print "in" Else Print "out"
      Print "(-10,5)  " ;Tab(12);
      If inpolygon(exagon(),Type<Point>(-10,5)) Then Print "in" Else Print "out"
      Print "(0,5)  " ;Tab(12);
      If inpolygon(exagon(),Type<Point>(0,5)) Then Print "in" Else Print "out"
      Print "(10,5)  " ;Tab(12);
      If inpolygon(exagon(),Type<Point>(10,5)) Then Print "in" Else Print "out"
      Print "(8,5)  " ;Tab(12);
      If inpolygon(exagon(),Type<Point>(8,5)) Then Print "in" Else Print "out"
      Print "(10,10)  " ;Tab(12);
      If inpolygon(exagon(),Type<Point>(10,10)) Then Print "in" Else Print "out"
      Print
  End Select
Next z
Sleep